In recent years fly-by-wire (FBW) and other flight and vehicle control systems (FCSs) have been developed for the improvement of safety and performance in the operation of manned and unmanned aircraft and other vehicles, such as spacecraft.
The goals of safety and performance in vehicle control have traditionally been considered to be conflicting: for example, the safety of an aircraft intended for commercial passenger transport can be improved by increasing its stability, at the cost of rapid performance in response to control inputs; while the performance of military and sport aircraft can be improved by making them partially or even wholly unstable. Properly-configured automatic control systems such as FCSs can be used to reconcile the conflicting needs of stability and performance without loss of safety.
It must be borne in mind, however, that decreased stability for improved performance tends to increase control workload associated with safe flight of commercial and other vehicles or aircraft, and can in some circumstances make safe flight impossible without the assistance of properly-configured automatic FCSs. Both safety and performance are critically reliant upon the availability and integrity of the FCS.
Operational economics also tend to impose high expectations on FCSs, as well as on a large number of other aircraft systems—requiring, in some cases, that an aircraft be able to operate safely with one or more failed system elements for a limited amount of time, until for example the aircraft is able to return to its maintenance base.